Show base-currency equivalent next to foreign-currency account balances

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

src/routes/(app)/companies/[companyId]/accounts/+page.svelte

@@ -767,6 +767,13 @@
 					<p class="text-2xl font-bold {balanceClass(acct.balance)}">
 						{formatAmount(acct.balance, acct.currency)}
 					</p>
+					{#if acct.currency !== data.company.currency && acct.fxRateToBase}
+						{@const baseEquivalent = (Number(acct.balance) * Number(acct.fxRateToBase)).toFixed(2)}
+						<p class="text-xs text-gray-500 dark:text-gray-400">
+							≈ {formatAmount(baseEquivalent, data.company.currency)}
+							<span class="text-gray-400 dark:text-gray-500">(@ {Number(acct.fxRateToBase)})</span>
+						</p>
+					{/if}
 
 					{#if acct.accountType === 'credit_card' && acct.creditLimit}
 						{@const pct = utilisation(acct.balance, acct.creditLimit)}